HORIZON vs PARA: which needs more amplifier?

The Moondrop HORIZON is 32Ω at 94.1 dB/mW; the Moondrop PARA is 8Ω at 80.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.

The PARA needs 14.1 dB more than the HORIZON to reach the same loudness — 100 mW against 3.9 mW.

The numbers that decide it

SpecificationHORIZONPARA
Impedance32 Ω8 Ω
Sensitivity94.1 dB/mW80.0 dB/mW
Sensitivity (voltage)109.0 dB/V101.0 dB/V
Power for 100 dB3.9 mW100 mW
Voltage for 100 dB0.35 V0.89 V
Current for 100 dB11.0 mA111.8 mA
Highest source impedance
that leaves them alone (one-eighth rule)
4.00 Ω1.00 Ω
Sources that reach 100 dB
out of 280
280130

Where the two part company

150 of the 280 sources have the power for the HORIZON but not for the PARA — Apple USB-C dongle (US), Apple USB-C dongle (EU), Generic CX31993 dongles, 147 more.

12 sources are low enough in output impedance for the HORIZON under the one-eighth rule but not for the PARA (FiiO KA13, FiiO K11, Schiit Vali 2+, 9 more).

130 of the 280 sources here reach 100 dB on both.

What each one needs from 80 to 105 dB

The PARA is more demanding than 100% of the 567 non-electrostatic models in this database; the HORIZON than 79%.

dB SPLHORIZON powerHORIZON voltagePARA powerPARA voltage
800.04 mW35 mV1.0 mW89 mV
850.12 mW63 mV3.2 mW0.16 V
900.39 mW0.11 V10 mW0.28 V
951.2 mW0.20 V32 mW0.50 V
1003.9 mW0.35 V100 mW0.89 V
10512 mW0.63 V316 mW1.59 V

The cheapest source that satisfies both

SourcePriceHeadroom, HORIZONHeadroom, PARAOutput impedanceNoise
FiiO KA11$2917.1 dB0.9 dB0.7 Ω1.7 µV
JDS Labs Atom+ (2nd gen)$9924.1 dB4.0 dB0.7 Ω1.99 µV
FiiO KA15$10916.7 dB1.6 dB0.8 Ω1.7 µV

Of the 280 sources here, 130 reach 100 dB on both. 53 of them also publish an output impedance low enough for both under the one-eighth rule and a noise figure that stays below the audible-hiss threshold with both.

The cheapest of the 53 is the FiiO KA11, at $29. It leaves 17.1 dB of headroom on the HORIZON and 0.9 dB on the PARA, its output impedance is 0.7 Ω against a one-eighth limit of 4.00 Ω and 1.00 Ω, and its noise figure puts the hiss floor 26 dB and 34 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.

Try any other source.

What each sheet prints, and what it is worth

ModelAs printedToleranceStandard
HORIZON20Hz-34kHz (IEC61094, Free Field)not printedIEC61094 (free field)
 20Hz- 20kHz (IEC60318 4, -3dB)-3 dBIEC60318-4
PARA15-53kHz (IEC61094, Free Field)not printedIEC61094 (free field)
 20-20kHz (IEC60318-4, -3dB)-3 dBIEC60318-4

Moondrop prints two ranges, “20Hz-34kHz (IEC61094, Free Field)” and “20Hz- 20kHz (IEC60318 4, -3dB)”, for the HORIZON and two ranges, “15-53kHz (IEC61094, Free Field)” and “20-20kHz (IEC60318-4, -3dB)”, for the PARA.

Both sheets print a tolerance, which is rare enough to be worth pointing at: only 58 of the 490 models with a printed range do. These two ranges can be set against each other, because each of them says how far down the response is allowed to be at the ends.

Not a measurement; maker by maker.

Both pages in full

Both have a page of their own. In full: Moondrop HORIZON and Moondrop PARA. Every figure on this page comes from what Moondrop published, or is derived from it — what that maker publishes, counted.

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